A thrilling first week of tennis in Melbourne is about to come to a close, but before it does so, there are still some tantalizing matches left to be played.  One of them is the third-round contest between John Isner and Feliciano Lopez.  They were fortunate to land in the weaker half of the draw, which became even more open after a few noteworthy early upsets.  Each will be anxious to make the most of his good fortune, but only one of them can proceed to the fourth round.

It is anyone's guess really which of these competitors is poised to continue his Australian Open campaign.  Neither started off 2016 particularly well.  Lopez lost his opening match in Doha before heading to Melbourne, while Isner did only one better by winning a match in Auckland before bowing out in the quarterfinals and coming over to Australia.  Isner enjoys the higher ranking at No. 11, but Lopez is only eight places behind him.  They have also arguably underperformed at the majors.  Isner has surprisingly rarely made the second week of a major and has just a handful of fourth-round appearances and one quarterfinal finish to his name.  Lopez has been a bit more successful with multiple quarterfinal and fourth-round finishes, but like Isner, he usually makes his exit around this stage.  

Their résumés and rankings are not the only areas where these two are close, however.  Their past encounters have been close as well.  They have met six times, and fittingly they have split those meetings at three apiece.  It will probably come as no shock to anyone that there have been many tiebreaks over the course of those six encounters as well.  Given how tight this rivalry is, it is nearly impossible to determine which man has the mental edge coming into this seventh meeting, but a case could be made that it is Lopez.  He was victorious in their only two encounters at a major, one of which was a five-set victory at this venue three years ago in this very same round.  It may not be much to draw on, but there is no telling what can go through a player's mind when things get tight.

There is every reason to believe that this next meeting will be a tight one too, since their games are so similar.  Each man is known for his serve, which often results in a fair amount of aces.  Isner has the advantage on the second delivery, but Lopez reaps the rewards that come with being left-handed.  Both also favor the quicker surfaces and primarily inflict damage on an opponent via the forehand wing.  The one stroke where they greatly differ is in the backhand, and it is the Spaniard's backhand that could have the most impact on the outcome of this match.  Isner's backhand may not be the ferocious weapon that his serve or forehand is, but it is solid and mostly reliable.  The same cannot be said for Lopez's.  There is a huge gap between what he can do from that side and with his forehand.  That said, it does not mean it cannot be effective in this match.  Lopez usually opts to slice from that side, and if he is hitting that slice well, it is going to be a long day for the towering Isner trying to dig those up, especially if he is still coping with a niggling back issue.  If Lopez is missing that shot in the net, or it is not skidding through the court, however, he is going to find himself at Isner's mercy.

Fans watching this duo should settle in for a long battle.  The rallies are not apt to be long, but history suggests that the sets and subsequently the match will be.  History also suggests that this is a 50-50 contest, but assuming Lopez has sufficiently recovered from his five-setter in the previous round, it might be 51-49 in his favor.  He has the lefty advantage with his serve on the big points.  He has gotten the better of Isner at the majors, and he has not faltered at this stage of a major as frequently as the American.  It is a close call, but the subtle nod goes to Lopez to inch his nose out in front in this rivalry.

There are many fresh faces in the third round of this year's Australian Open, and it is thanks to what can only be described as the decimation of so many of the women's seeds.  Two women who have thus far managed to avoid the upset bug are Madison Keys and Ana Ivanovic.  They have successfully navigated their way to the third round, but for one of them, their Australian Open dream is about to come to an end.  

It can be easy to assume that Ivanovic is the player destined to move though to the round of 16.  She has been around a long time and has established herself as a top player with 15 singles titles to her name.  She is a former No. 1 who won Roland Garros in 2008 and reached the final of the Australian Open that year.  

But an Ivanovic victory on Saturday would technically be considered an upset, since it is Keys who is the higher seed.  The young American owns just a solitary singles title and has struggled with injuries and consistency during the week-in,-week-out grind of the tour.  She came up with the goods at the majors last year, though, reaching the second week at three of the four, and she is keen to build on that trend once again, starting here in Melbourne.

The good news for Keys is that she comes into the match with the superior weaponry.  Ivanovic has a powerful forehand and gets decent zip on her backhand and serve, but not like Keys.  The American boasts the kind of power that rivals that of players like Serena Williams and Petra Kvitova.  As a result, she is better equipped to turn defense into offense with a single stroke and should have Ivanovic doing most of the running.  And while the Serb is a better mover than the 15th seed, her movement is not exceptional enough for her to keep routinely tracking down balls to frustrate Keys into giving up unforced errors.  Because of this, Ivanovic is going to have to go outside her comfort zone.  When she gets a look at a second serve, she has to pounce.  She has to be willing to take risks and play closer to the lines to get Keys out of position, or more often than not, she is going to find Keys dictating the rallies and terms of the match.

It is stressful enough when a player knows that the onus is on her to raise the level of her game, but even more so if she has not had much of a reason to feel confident with her current form.  That is the position that Ivanovic finds herself in coming into this encounter.  She lost both of her opening matches in Brisbane and Sydney, and it has not been completely smooth sailing for her here despite winning her matches in straight sets.  Of course, her progression to this point has also been less taxing than it has been for Keys. Ivanovic has won her only other encounter against the American, and she has accumulated more experience competing at the majors, which could count for something.  Then again, the fact that Keys has been more severely tested could prove beneficial in this match.  The Serb has a tendency to panic when things go wrong, whereas Keys can be secure in the knowledge that she has already faced and overcome adversity through her first couple of rounds.  Additionally, this is the site of her first breakthrough at a major, and it is not uncommon for competitors to play great where they have produced some of their best tennis in the past.  And finally, there is simply the fearlessness of youth that is apt to have her swinging away more freely than the former No. 1.

If Keys is swinging freely and begins to tap into her best form, it is going to be a long night for Ivanovic.  She possesses the more powerful weapons and generally the more positive attitude in the face of any hurdles.  One cannot underestimate Ivanovic.  She has accomplished too much in her career for that, and she will fight to the very last ball.  But in the end, this is Keys' match to win or lose, and if she plays within herself, she is going to wind up in the fourth round.